bioRxiv Science⌕ Search

bioRxiv · 10.1101/2022.05.05.490811

Sinking a giant: quantitative macroevolutionary comparative methods debunk qualitative assumptions

Abstract

Myhrvold et al.1 suggest that our inference of subaqueous foraging among spinosaurids2 is undermined by selective bone sampling, inadequate statistical procedures, and use of inaccurate ecological categorizations. Myhrvold et al.1 ignore major details of our analyses and results, and instead choose to portray our inferences as if they were based on qualitative interpretations of our plots, without providing additional analyses to support their claims. In this manuscript, we thoroughly discuss all the concerns exposed by Myhrvold et al.1. Additional analyses based on our original datasets2 and novel data presented by Myhrvold et al.1 do not change our original interpretations: while the spinosaurid dinosaurs Spinosaurus and Baryonyx are recovered as subaqueous foragers, Suchomimus is inferred as a non-diving animal.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Fabbri, M., Navalon, G., Benson, R. B., Pol, D., O'Connor, J., Bhullar, B.-A. S., Erickson, G., Norell, M. A., Orkney, A., Lamanna, M. C., Zouhri, S., Becker, J., Dal Sasso, C., Bindellini, G., Maganuco, S., Auditore, M., Ibrahim, N.. 2022-05-06. Sinking a giant: quantitative macroevolutionary comparative methods debunk qualitative assumptions. https://doi.org/10.1101/2022.05.05.490811

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

Constraining Palaeogeography and Palaeotides for the Cambrian using cnidarian medusae

The ocean tides influence key Earth system processes at a range of spatial and temporal scales. It is known that the geometry of ocean basins is the leading controller of tidal energetics, so well-constrained palaeogeographic reconstructions and tidal properties for Earths past are imperative when investigating other Earth system processes. Here, we present a novel way to constrain both deep-time tidal model results and reconstructions, by combining palaeoecology with sedimentology. We compare new palaeo-tidal model simulations for the Cambrian period, significant for the early origin and radiation of major animal fauna, to tidal proxies. One of the most abundant soft-bodied organisms preserved during this time are cnidarian medusae (jellyfish). A total of 17 cnidarian medusae localities were obtained through the literature, which had an adequate global distribution and occurred at regular intervals throughout the period of study. In some locations there were also estimates of palaeo-tidal range. Our results show a good agreement between the simulations and proxy data. In the few locations where there is disagreement, it is proposed that the palaeogeographic reconstructions are missing details, e.g., island chains, and our results allow for the palaeogeographic reconstructions to be improved. The proxy method presented is promising and can be applied to other time-periods with different marine fossils, particularly at evolutionary and extinction periods where the marginal marine environment is of importance.

paleontology↗

Palaeontological evidence for community-level decrease in mesopelagic fish size during Pleistocene climate warming in the eastern Mediterranean

Mesopelagic fishes are an important element of marine food webs, a huge, still mostly untapped food resource, and great contributors to the biological carbon pump, whose future under climate change scenarios are unknown. The shrinking of commercial fishes within decades has been an alarming observation, but its causes remain contended. Here, we investigate the effect of warming climate on mesopelagic fish size in the eastern Mediterranean Sea during a glacial-interglacial-glacial transition of the Middle Pleistocene (marine isotope stages 20-18; 814-712 Kyr B.P.), which included a 4 {degrees}C increase of global seawater temperature. Our results based on fossil otoliths show that the median size of lanternfishes, one of the most abundant groups of mesopelagic fishes in fossil and modern assemblages, declined by ~35% with climate warming at the community level. However, individual mesopelagic species showed different and often opposing trends in size across the studied time interval, suggesting that climate warming in the interglacial resulted in an ecological shift toward increased relative abundance of smaller-sized mesopelagic fishes due to geographic and/or bathymetric distribution range shifts, and the size-dependent effects of warming.

paleontology↗

Taxon cycles in Neotropical mangroves

The concept of taxon cycle involves successive range expansions and contractions over time through which a species can indefinitely maintain its core distribution. Otherwise, it becomes extinct. Taxon cycles have been defined mostly for tropical island faunas, examples from continental areas are scarce and similar case studies for plants remain unknown. Most taxon cycles have been identified on the basis of phylogeographic studies, and straightforward empirical evidence from fossils is lacking. Here, empirical fossil evidence is provided for recurrent Eocene to present expansion/contraction cycles in a mangrove taxon (Pelliciera), after a Neotropical-wide study of the available pollen records. This recurrent behavior is compatible with the concept of taxon cycle from biogeographical, chronological and ecological perspectives. The biotic and abiotic drivers potentially involved in the initiation and maintenance of the Pelliciera expansion/contraction cycles are analyzed, and the ecological and evolutionary implications are discussed. Whether this could be a trend toward extinction is considered under the predictions of the taxon cycle theory. The recurrent expansion and contraction cycles identified for Pelliciera have strong potential for being the first empirically and unequivocally documented taxon cycles and likely the only taxon cycles documented to date for plants.

paleontology↗